
where \(Q_i \in \mathbb {R}^{m \times m}\)  is a positive definite matrix. In particular, different kinds of graphs are considered, included four digraphs: directed cycle graph, directed exponential graphs with \(e = 2, 4, 6\) , and four undigraphs: cycle graph, Erdos–Renyi random graphs with the connectivity probability \(p = 0.05, 0.1, 0.3\) . The directed exponential graph with \(n\)  nodes is generated by the rule that each node \(i\)  can send information to the nodes \((i+2^j)\mod {n}\) , \(j=0, 1, \cdots , e-1\) . The weight matrices \(W_1\)  and \(W_2\)  are constructed by the Laplacian method [1]}.
